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07 May 2012

What's old is new once again. I'd actually written most of this in February, when Heartland was in the news. But between one thing and another, hadn't posted it. Now that they're in the news again, it seems once again to be apt. As usual, my interest is on the science. Since a number of Heartland supporters are saying things in the vein of Heartland made a misstep in acting as they did, because it takes away from their message on the science. The supporters think Heartland is doing well on the science.

Now that I've looked in to what Heartland Institute has had to say on sea ice, I can say with confidence that they are not doing well on the science. They don't know (or lie about) the difference between ice area and ice extent, don't know how much area of ice there is, don't know where it forms, make up numbers even if you ignore the difference between area and extent, lie about what authors say in their scientific papers, treat 2 years as plenty for establishing a climate trend if it is in one direction, but ignore the 30 year trends when it isn't, don't know the difference between sea ice and ice shelves, don't understand how sea level changes, and others I'll let you classify yourself.

The gory details, examples being from their web site, are below the fold. A different point is, I don't expect everyone to be expert on sea ice, or even pay attention to it. If Heartland had ignored sea ice, that's fine (at least it is if they're not saying things which require understanding sea ice). But they chose to write about it. And the people whose articles I'm quoting are Jay Lehr, their science director, and James M. Taylor, a senior fellow for the Heartland Institute focusing on environmental issues. In other words, major players in deciding what Heartland says about science, not someone who might once have said something stupid about sea ice while passing through the office.

Sea ice plays a key role in regulating the surface exchange of heat, moisture, and salt between the Earth's atmosphere and the oceans. It is a high-latitude phenomenon found only in the Arctic Ocean and in the oceans around Antarctica. The local amount changes with the season, but at any given time, sea ice worldwide covers an area larger than the North American continent.

The first sentence is true; those are among the reasons that I study it.

Second sentence is badly false. Sea ice is found in many places in the northern hemisphere outside of the Arctic Ocean. This includes the Bering Sea, Sea of Okhotsk, Sea of Japan, Bay of Bohai, Hudson Bay, the Labrador Sea, Gulf of St. Lawrence, and the Baltic Sea. It also includes inland waters such as the North American Great Lakes, the Sea of Azov, and the northern Caspian Sea. In all, at maximum extent, something like half the area of northern hemisphere ice on water (whether ocean, sea, or lake) is outside the Arctic Ocean.

And the third sentence, even if not exactly important, is also badly false. One may visitCryosphere Today to view global ice area values. At maximum, it is 22-23 million square km, and minimum is 15-16 million square km. The area of North America is about 24.7 million square km. I'm surprised that even at maximum area, global sea ice does not cover more area than North America. It would be true to say that at any time, sea ice covers more area than the United States (which is about 10 million square km).

In the Arctic Ocean, floating sea ice (as opposed to ice shelves, which generally remain attached to the glacier that produced them) covers on average 14 million to 16 million square kilometers in late winter and 7 million to 9 million square kilometers at the end of summer. In Antarctica, sea ice covers from 17 million to 20 million square kilometers in late winter; only about 3 million to 4 million square kilometers remains at the end of summer.

Sentence 1 is false. Sea ice area (as opposed to extent) in the Northern Hemisphere (not just the Arctic Ocean) is 12-14 million square km in late winter (see NSIDC). In the summer, area is down to 4-5 million square km. And sentence 2 is false. Antarctic area has a maximum of 14-15 million square km, not 17-20. Its minimum is 2-3 million square km, not 3-4.

If we decide that Lehr doesn't know (or doesn't care) about the difference between sea ice area -- the area occupied by sea ice, and which is how he describes it -- and sea ice extent -- the area of grid cells in a satellite analysis which have some ice, he's still wrong. The Arctic max is correct, but late summer's area is 6-8 million square km, not 7-9. (And, since his article, we've seen it drop to 3; and at the time of his article it was already known that there was a declining trend, more later.) In the Antarctic, maximum extent is 18-19 million square km, not 17-20. Minimum is 2-4, not 3-4.

Lehr is noted as having a PhD, but no mention is made of what area.

James M. Taylor is a senior fellow for the Heartland Institute focusing on environmental issues (http://heartland.org/james-m-taylor), so, again should be someone Heartland considers reliable in his environmental science writing. His bachelor's is noted merely as being from Dartmouth, no area mentioned, and he has a law degree. No mention of any science background.

A study published in Geophysical Research Letters (Winsor, P., "Arctic sea ice thickness remained constant during the 1990s," Volume 28: 1039-1041 (2001)) found the same to be true in the Arctic. The study concluded, "mean ice thickness has remained on a near-constant level around the North Pole from 1986-1997."

The red flag about arguing trends from too short periods arises right off. 11 years is awfully short to make a climate statement.

But, also, the section head, bolded in the original, is not supported by the paper cited -- header says the ice is thickening, but the article says near-constant. If Taylor read the article he's quoting, he'd have seen this direct statement (emphasis mine) "In fact, a linear regression gives a slight increasing trend for the whole period, although not signicant." If he didn't, that's another problem.

Now, if you go ahead and read the full science article, which I always recommend, you'll see that Winsor was writing in response to Rothrock et al, 1999. In other words, Taylor had another article
available -- one that did cover a climatically meaningful period (1958-1997). That article documented a long term trend, a climate trend, towards ice thinning. From 3.1 m to 1.8 m. Winsor took (scientific) issue with a statement in the 1999 paper about a trend existing in the 1990s that Rothrock et al. had made. So, quite properly, tracked down additional data to see what was the case. His conclusion is as above.

Science keep working, and we have another decade of sea ice thickness data. Now it includes satellite observations. And it still shows a climate trend of thinning. It's an interesting topic to pursue on its own -- how has the scientific understanding of sea ice thickness changed from the early 1980s to present. You can see several back and forths between scientists as they try to figure it out.

http://news.heartland.org/newspaper-article/2003/01/01/still-no-consensus-global-warming-scienceSea-Ice Season in Antarctic Growing LongerA study reported in Annals of Glaciology (Vol. 34: 435-440 (2002)) found sea ice in the Southern Ocean region surrounding Antarctica has exhibited mixed trends of growth and shrinkage, depending on the area studied. However, according to the study’s author, “the area of the Southern Ocean experiencing a lengthening of the sea-ice season by at least 1 day per year over the period 1979-99 is 5.6 x 10(6) km2, whereas the area experiencing a shortening of the sea-ice season by at least 1 day per year is 46 percent less than that, at 3.0 x 10(6) km2.”

Accordingly, “a much larger area of the Southern Ocean experienced an overall lengthening of the sea-ice season over the 21 years 1979-99 than experienced a shortening.” The lengthening sea-ice season is the opposite of what climate models predict would happen in a warming world.

As this year’s summer ice approached its annual September minimum, satellite photographs revealed more ice in 2009 than in 2008, which in turn retained more ice than 2007.
...In 2007, Arctic sea ice covered approximately 4.5 million square kilometers at its summer minimum. In 2008, the ice covered nearly 5 million square kilometers at its summer minimum. This summer, Arctic sea covered approximately 1 million square kilometers more than 2007 sea ice as the season approached its September sea ice minimum.

Figures for the September monthly average extent (a figure notably higher than the summer minimum, which only occurs for a few days) from NSIDC (and, notice, he's confused extent for cover -- area.)
2007 4.30
2008 4.68
2009 5.36
2010 4.90
2011 4.61
He doesn't give his source for information. But, if we ignore the difference between area and extent, and use JAXA figures, which run about 0.2 million km^2 higher than NSIDC, his initial statements aren't directly wrong. They are misleading, in that 2 years does not establish a climate trend. And, if he's even-handed, the 2 years of decline which followed would warrant an equally strong statement about Arctic ice cover collapsing. I find no such article.

http://heartland.org/policy-documents/noaa-obama-administration-launch-climate-propaganda-project
(February 9, 2010)What Scott conveniently forgets to mention is that NASA has determined that variable local wind patterns, rather than global warming, caused the substantial retreat of Arctic sea ice in 2007 by blowing sea ice east toward Greenland where it could escape into the North Atlantic Ocean rather than blowing sea ice west where it remains trapped in northern latitudes by the Alaskan and Siberian land masses.

Still more deceitfully, Scott failed to note that minimum Arctic sea ice has rebounded by 25 percent since 2007, despite the unfavorable local wind patterns. Even the most novice student of Arctic sea ice knows of substantial recent growth in Arctic sea ice, yet Scott deliberately left it out in order to present an erroneous portrait of Arctic ice retreat.

In the same paragraph in which he paints a deceitful picture of Arctic sea ice, Scott writes, “In 2002, some 3,250 square kilometers of the Larsen B Ice Shelf on the Antarctic Peninsula shattered over a period of just five weeks.” True, but once again Scott leaves out important information that dispels the myth that global warming is to blame. Even the most novice student of Antarctic sea ice knows that Antarctic sea ice extent has been growing ever since NOAA satellite instruments began measuring it in 1979. Indeed, for much of the past few years (including 2007, the year of Scott’s Arctic sea ice deception) Antarctic sea ice has been at record extent. The Larsen B Ice Shelf collapse in 2002 is clearly an exception to the rule of expanding Antarctic sea ice, but Scott deliberately hides that fact.

First paragraph there has a common distortion -- '... local wind patterns, rather than global warming ...' One of the things which establishes what the wind patterns are like is the temperature distribution. This leads to some of the interesting features about planetary circulation, such as why the jet stream is located over mid latitudes, rather than near the poles or equator. Change the temperature distribution, say by warming some areas more than others, and you change the wind patterns.

Second, in talking about Scott, he attributes 'deceit' in failing to observe 2 years of 'rebound'. Which rather attracts the label to Taylor for his failure to acknowledge the 2 years of decline since this article. And Taylor is, at this point, ignoring information we have regarding the decline in sea ice thickness -- which continued from 2007 to the time of his writing. Ignoring being ... convenient for deceit. Whether Taylor was deceitful, or lazy (failing to look for information), or what, I don't know. But he likes the label 'deceitful' when it is someone else involved.

Third paragraph, Taylor shows that he doesn't know the difference between sea ice and ice shelves that his colleague at Heartland, Lehr, clearly noted 5 years earlier. Ice shelves in Antarctica have indeed been retreating. Sea ice has, arguably, been expanding in Antarctica (which, if true, indicates that climate models did pretty well even in the early 1990s).

Note, by the way, that Heartland lists this as a policy document. For my own taste, I prefer policy to be based on things that are true.

It is true that melting sea ice will raise sea level. Grumbine, 1997 is, apparently, the oldest documented calculation of the effect. It appeared in the scientific literature in 2007 -- Noerdlinger and Brower. http://www.physorg.com/news5619.html for an easier to reach site (and note the date -- the experiment was completed by 2005, publication took a while). Journal cite is: Peter D. Noerdlinger and Kay R. Brower, in The Geophysical Journal International, 170, pp. 145-150, 2007 The melting of floating ice raises the ocean level. The DOI is 10.1111/j.1365-246X.2007.03472.x

1 comment:

Welcome

I'll be trying what seems to be an unusual approach in blogs -- writing to be inclusive of students in middle school and jr. high*, as well as teachers and parents (whether for their own information or to help their children). To that end, comments will have to pass a stricter standard than I'd apply for an all-comers site. It shouldn't be onerous, just keep to the topic and use clean language.

I expect it to be fun for all, however, as you really can get quite far in understanding the world, even climate, by understanding this sort of fundamental. If I get too much less fundamental, let me know where I went astray.

* Ok, I concede that not many middle school students will get everything. Even a fair number of adults will find some parts hard to follow. Still, some middle school kids will have fun. And almost everyone will follow a number of posts just fine.

Please see the comment policy for details. And the link policy for details about that. The latter is more open than you might expect.

About Me

In my day job I work on the oceanography, meteorology, climatology, glaciology end of my science interests, but I'm interested in everything, science or not. So I've also been on stage in a production of Comedy of Errors, run an ultramarathon, and been to Epidaurus, Greece, to see a production of Euripides' Iphigenia among the Taurians
Prior to starting the current job, I was a post-doc in oceanography in the UCAR ocean modelling program, and earned my doctorate from the Department of the Geophysical Sciences at the University of Chicago (1989). My undergraduate degree involved Applied Math, Engineering, Astrophysics, and Glaciology.
Of course I don't speak for my employer, whoever that may be.